Statement of the Technical Field
The present invention relates to the processing electronic mail and more particularly to limiting the transmission of electronic mail based upon the identity of the transmission source.
Description of the Related Art
Historically, the print medium served as the principal mode of unsolicited mass advertising on the part of the direct marketing industry. Typically referred to as “junk mail”, unsolicited print marketing materials could be delivered in bulk to a vast selection of recipients, regardless of whether the recipients requested the marketing materials. With an average response rate of one to two percent, junk mail has been an effective tool in the generation of new sales leads. Nevertheless, recipients of junk mail generally find the practice to be annoying. Additionally, postage for sending junk mail can be expensive for significant “mail drops”. Consequently, the direct marketing industry constantly seeks equally effective, but less expensive modalities for delivering unsolicited marketing materials.
The advent of electronic mail has provided much needed relief for direct marketers, as the delivery of electronic mail to a vast number of targeted recipients requires no postage. Moreover, the delivery of unsolicited electronic mail can be an instantaneous exercise and the unsolicited electronic mail can include embedded hyperlinks to product or service information thus facilitating an enhanced response rate for the “mail drop”. Still, as is the case in the realm of print media, unsolicited electronic mail remains an annoyance to consumers worldwide.
The term “spam” has been assigned to unsolicited commercial electronic mail. For many, spam represents a scourge upon the Internet consuming unnecessary bandwidth, excess computing resources and the time of millions of Internet users. Ironically, while electronic mail in the past has been viewed as the “killer” application designed to provide vast efficiencies in the field of global communications, spam threatens to minimize the effectiveness of electronic mail by imposing upon electronic mail users the obligation of screening incoming messages to detect spam. Consequently, many avoid the use of electronic mail simply to avoid spam.
Several techniques have been developed to combat the spread of spam. Spam filters have been disclosed in which textual patterns within electronic mail can be correlated to known patterns associated with spam. Where an electronic message includes text matching a known spam pattern, the delivery of the electronic message can be suppressed. By comparison, many convention electronic mail clients include functionality for identifying a message as spam. Upon identifying a message as spam, the domain of the sender can be associated with spam such that subsequent messages transmitted from the domain of the sender can be suppressed as spam.
Nevertheless, the skilled artisan will recognize that each of the foregoing spam combating techniques can be characterized at best as client-side application layer techniques. In this regard, so long as the number and nature of individual electronic mail clients vary, so too will the effectiveness of the spam combating techniques. Similarly, electronic mail filtering applications can differ widely and, again, depending upon the implementation, the effectiveness can vary as well. Notably, all electronic mail clients exchange information at the protocol layer using a universally adopted mail protocol—the simple mail transfer protocol (SMTP). Accordingly, what is needed is a more effective methodology for combating spam exclusive of the client side mail client which can span varying mail clients while maintaining a constant level of effectiveness.